#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Pines de Hardware
#define BTN_SI     2   // Botón SÍ / Confirmar
#define BTN_NO     3   // Botón NO / Cancelar
#define BUZZER_PIN 8   // Buzzer

// Dimensiones de los ojos
int eyeW = 42;
int eyeH = 38;
int leftX = 8;
int rightX = 78;
int eyeY = 13;

// Estados del sistema
enum GameState { STATE_WELCOME, STATE_PET, STATE_QUIZ, STATE_RESULT };
GameState currentState = STATE_WELCOME;

// Estructura de Preguntas Dinámicas
struct DynamicQuestion {
  char textOp[16];
  char textAns[16];
  bool isTrue;
};

DynamicQuestion currentQ;
int currentQuestionIndex = 0;
int score = 0;
unsigned long lastBlinkTime = 0;

// --- MELODÍA CONSTANTE EN SEGUNDO PLANO (NON-BLOCKING) --- //
int melody[] = { 262, 294, 330, 392, 330, 294, 262, 196, 220, 247, 262, 262 };
int noteDurations[] = { 200, 200, 200, 300, 200, 200, 200, 300, 200, 200, 250, 250 };
int totalNotes = sizeof(melody) / sizeof(melody[0]);

int currentNote = 0;
unsigned long lastNoteTime = 0;
bool isMelodyActive = true;

void playBackgroundMelody() {
  if (!isMelodyActive) return;

  unsigned long currentMillis = millis();
  if (currentMillis - lastNoteTime >= noteDurations[currentNote] + 40) {
    lastNoteTime = currentMillis;
    tone(BUZZER_PIN, melody[currentNote], noteDurations[currentNote]);
    currentNote = (currentNote + 1) % totalNotes;
  }
}

// --- DIBUJO DE OJOS Y ANIMACIONES --- //

void drawEyes(int hLeft, int hRight, int yOffset = 0) {
  display.clearDisplay();
  if (hLeft > 0) {
    display.fillRoundRect(leftX, eyeY + yOffset + (eyeH - hLeft) / 2, eyeW, hLeft, 8, SSD1306_WHITE);
  }
  if (hRight > 0) {
    display.fillRoundRect(rightX, eyeY + yOffset + (eyeH - hRight) / 2, eyeW, hRight, 8, SSD1306_WHITE);
  }
  display.display();
}

void blink() {
  for (int h = eyeH; h >= 4; h -= 6) {
    drawEyes(h, h);
    delay(15);
  }
  drawEyes(2, 2);
  delay(60);
  for (int h = 4; h <= eyeH; h += 6) {
    drawEyes(h, h);
    delay(15);
  }
  drawEyes(eyeH, eyeH);
}

void drawHeart(int x, int y) {
  display.fillCircle(x - 8, y - 5, 8, SSD1306_WHITE);
  display.fillCircle(x + 8, y - 5, 8, SSD1306_WHITE);
  display.fillTriangle(x - 16, y - 2, x + 16, y - 2, x, y + 16, SSD1306_WHITE);
}

void animHappy() {
  for (int i = 0; i < 2; i++) {
    drawEyes(eyeH, 6);
    delay(150);
    drawEyes(eyeH, eyeH);
    delay(150);
  }
}

void animSad() {
  display.clearDisplay();
  display.fillRoundRect(leftX, eyeY + 10, eyeW, 12, 4, SSD1306_WHITE);
  display.fillRoundRect(rightX, eyeY + 10, eyeW, 12, 4, SSD1306_WHITE);
  display.display();
  delay(500);
}

void animWin() {
  for (int i = 0; i < 2; i++) {
    drawEyes(eyeH, 3);
    delay(300);
    drawEyes(eyeH, eyeH);
    delay(150);
  }

  display.clearDisplay();
  drawHeart(29, 32);
  drawHeart(99, 32);
  display.display();
}

void animLaugh() {
  for (int i = 0; i < 4; i++) {
    drawEyes(6, 6, -6);
    delay(80);
    drawEyes(6, 6, 6);
    delay(80);
  }
  drawEyes(eyeH, eyeH);
}

// --- EFECTOS DE SONIDO --- //

void soundCorrect() {
  isMelodyActive = false;
  tone(BUZZER_PIN, 523, 100); delay(120);
  tone(BUZZER_PIN, 784, 150); delay(160);
  noTone(BUZZER_PIN);
  isMelodyActive = true;
}

void soundWrong() {
  isMelodyActive = false;
  tone(BUZZER_PIN, 300, 150); delay(180);
  tone(BUZZER_PIN, 150, 250); delay(260);
  noTone(BUZZER_PIN);
  isMelodyActive = true;
}

void soundWinMelody() {
  isMelodyActive = false;
  int notes[] = {523, 659, 784, 1046};
  for (int i = 0; i < 4; i++) {
    tone(BUZZER_PIN, notes[i], 120);
    delay(140);
  }
  noTone(BUZZER_PIN);
  isMelodyActive = true;
}

void soundLaughBurla() {
  isMelodyActive = false;
  for (int i = 0; i < 3; i++) {
    tone(BUZZER_PIN, 800, 70); delay(90);
    tone(BUZZER_PIN, 600, 90); delay(110);
  }
  tone(BUZZER_PIN, 300, 300); delay(320);
  noTone(BUZZER_PIN);
  isMelodyActive = true;
}

// --- GENERADOR ALEATORIO DE PREGUNTAS --- //

void generateRandomQuestion() {
  int opType = random(0, 4); // 0: Suma, 1: Resta, 2: Multiplicación, 3: División
  int a = 0, b = 0, realResult = 0;
  bool forceCorrect = (random(0, 2) == 1);

  switch (opType) {
    case 0: // Suma
      a = random(1, 20);
      b = random(1, 20);
      realResult = a + b;
      snprintf(currentQ.textOp, sizeof(currentQ.textOp), "%d + %d =", a, b);
      break;

    case 1: // Resta
      a = random(5, 25);
      b = random(1, a);
      realResult = a - b;
      snprintf(currentQ.textOp, sizeof(currentQ.textOp), "%d - %d =", a, b);
      break;

    case 2: // Multiplicación
      a = random(2, 10);
      b = random(2, 10);
      realResult = a * b;
      snprintf(currentQ.textOp, sizeof(currentQ.textOp), "%d x %d =", a, b);
      break;

    case 3: // División
      b = random(2, 9);
      realResult = random(2, 10);
      a = b * realResult;
      snprintf(currentQ.textOp, sizeof(currentQ.textOp), "%d / %d =", a, b);
      break;
  }

  int displayedResult = realResult;
  if (!forceCorrect) {
    int offset = random(1, 4);
    displayedResult = (random(0, 2) == 0) ? (realResult + offset) : (realResult - offset);
    if (displayedResult < 0) displayedResult = realResult + offset;
  }

  snprintf(currentQ.textAns, sizeof(currentQ.textAns), "Es %d?", displayedResult);
  currentQ.isTrue = (displayedResult == realResult);
}

// --- INTERFAZ Y FLUJO --- //

void showWelcomeScreen() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(20, 10);
  display.println(F("¡BIENVENIDO!"));
  display.setCursor(10, 30);
  display.println(F("ROBOTICA EDUCATIVA"));
  display.display();
  
  soundWinMelody();
  delay(1500);
  blink();
  currentState = STATE_PET;
}

void showQuestion() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  display.setCursor(0, 0);
  display.print(F("PREGUNTA "));
  display.print(currentQuestionIndex + 1);
  display.print(F("/10"));
  display.drawLine(0, 10, 128, 10, SSD1306_WHITE);

  display.setCursor(0, 18);
  display.println(currentQ.textOp);
  display.setCursor(0, 28);
  display.println(currentQ.textAns);

  // Botones
  display.drawRect(0, 44, 58, 18, SSD1306_WHITE);
  display.setCursor(12, 49);
  display.print(F("[SI]"));

  display.drawRect(70, 44, 58, 18, SSD1306_WHITE);
  display.setCursor(82, 49);
  display.print(F("[NO]"));

  display.display();
}

void startQuiz() {
  currentState = STATE_QUIZ;
  currentQuestionIndex = 0;
  score = 0;
  generateRandomQuestion();
  showQuestion();
}

void processAnswer(bool userAns) {
  bool isCorrect = (userAns == currentQ.isTrue);

  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(5, 20);

  if (isCorrect) {
    score++;
    display.println(F("CORRECTO!"));
    display.display();
    soundCorrect();
    animHappy();
  } else {
    display.println(F("INCORRECTO"));
    display.display();
    soundWrong();
    animSad();
  }
  delay(600);

  currentQuestionIndex++;
  if (currentQuestionIndex < 10) {
    generateRandomQuestion();
    showQuestion();
  } else {
    currentState = STATE_RESULT;
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(15, 10);
    display.print(F("Puntaje: "));
    display.print(score);
    display.println(F(" / 10"));
    display.display();
    delay(1500);

    if (score >= 7) {
      soundWinMelody();
      animWin();
    } else {
      animLaugh();
      soundLaughBurla();
    }

    delay(2000);
    currentState = STATE_PET;
    drawEyes(eyeH, eyeH);
  }
}

// --- SETUP Y LOOP --- //

void setup() {
  pinMode(BTN_SI, INPUT_PULLUP);
  pinMode(BTN_NO, INPUT_PULLUP);
  pinMode(BUZZER_PIN, OUTPUT);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true);
  }

  // Genera semilla aleatoria usando ruido analógico
  randomSeed(analogRead(A0));
  showWelcomeScreen();
}

void loop() {
  playBackgroundMelody();

  if (currentState == STATE_PET) {
    if (millis() - lastBlinkTime > random(2000, 4500)) {
      blink();
      lastBlinkTime = millis();
    }

    if (digitalRead(BTN_SI) == LOW || digitalRead(BTN_NO) == LOW) {
      delay(200); // Debounce
      startQuiz();
    }
  } 
  else if (currentState == STATE_QUIZ) {
    if (digitalRead(BTN_SI) == LOW) {
      delay(200);
      processAnswer(true);
    } else if (digitalRead(BTN_NO) == LOW) {
      delay(200);
      processAnswer(false);
    }
  }
}